There are many applications known in which documents are fed along a paper path and then collated for further processing. Generally, the documents must be properly aligned when the collation is formed before further processing, such as stitching (stapling) or insertion into an envelope, can be performed. Heretofore, stitching apparatus have been structured to stitch in a fixed location relative to the collation being stitched. Typically, stitching is done either at the lead edge or at the trail edge of a collation which has been conveyed to and stopped adjacent to the stitching mechanism.
In some applications, the collation is formed and then stitched at a stacking area. However, such applications, for example in copying machines, are typically performed at a sufficiently slow speed to insure that the collation is properly squared before stitching is performed.
For example, U.S. Pat. No. 5,092,509 issued to Naito et al. on Mar. 3, 1992, discloses a sheet stapling apparatus in a copying machine including a sheet bin for accommodating sheets, a reference member for one side edge of the sheets in the bin, aligning means for urging the sheets in the bin to the reference member, stapling means for stapling the sheets in the bins, and control means for controlling the aligning means so that the aligning means urges the sheets to the reference member and is maintained at the urging position during the sheet stapling operation for the sheets in the bin.
In other applications conventional accumulators, i.e., collating machines, are used to assemble a collation which is then forwarded for stitching. Examples of conventional accumulators are shown in U.S. Pat. Nos. 5,178,379, 5,083, 769 and 4,925,180. Conventional accumulators, include conventional side guide structure that extends the length of the transport within the collator. Such guide structure has been used to maintain alignment of the sheets the entire time they are conveyed, for example, by an upper and lower O-ring belt transport to form a collation to ensure that the sheets of the collation are not skewed. Typically, such conventional side guide structure is laterally adjustable for handling different size sheets. Such conventional side guide structure is particularly suitable for accumulators having a stacking area that is easily accessible.
It is an object of the present invention to provide a side guide device that maintains alignment of sheets being accumulated and that is suitable for use in an accumulator having limited access to the stacking area.